Bland-Altman Research Articles

Evaluation of carp sperm respiration: fluorometry with optochemical oxygen sensor versus polarography

The primary function of spermatozoa is to fertilize the oocyte, which depends on their motility and is directly associated with their metabolic state. The oxygen consumption rate (OCR) of spermatozoa reflects the respiratory capacity of sperm mitochondria under various physiological conditions and is an essential marker of sperm quality. We determined the OCR of common carp (Cyprinus carpio) sperm using two respirometry methods: the conventionally used polarographic method with a Clark-type electrode and fluorometric assay with an Oxo Dish optochemical oxygen sensor. The latter was used for the first time to evaluate spermatozoa oxygen consumption in various metabolic states (under different treatments) at different dilution rates. These two methods were compared using Bland–Altman analysis, and the applicability of the optochemical oxygen sensor for evaluating carp sperm oxygen consumption was discussed. Sperm motility and progressive velocity parameters were also assessed to evaluate the effect of sperm respiration under different metabolic states and dilution rates and preincubation period on the physiological status of spermatozoa. The comparison of these respirometry methods clearly shows that while the polarographic method allows immediate measurement of oxygen levels after adding a sperm sample, the optochemical oxygen sensor has a priority in the amount of data obtained due to simultaneous measurements of several samples (e.g., different males, different fish species, repetitions of the same sample or various experimental conditions), even at a later time after adding sperm to the measuring chamber. However, the compared methods are complementary, and the proposed methodology can be applied to other fish species.

Reliability of a portable toe pressure photoplethysmography device compared to a stationary laser doppler flowmeter.

The study aimed to investigate the reliability of a portable toe pressure (TP) photoplethysmography device (PPG) by comparing it to a stationary laser Doppler flowmeter (LD) used in the Helsinki University Hospital. The study evaluated if lower limb arterial circulation could be reliably evaluated with the portable PPG which is more affordable and mobile than the stationary LD. TPs were measured from 102 toes of 54 patients in the vascular surgery outpatient clinic, vascular surgery ward and interventional radiology recovery ward of Helsinki University Hospital. According to the study protocol TPs were measured twice with the PPG device. If the difference between the values was over 10 mmHg, a third measurement was done and two of the closest values were selected for the final analysis. The lowest value displayed by the PPG device was 30 mmHg. Lower than 30 mmHg values were reported as 25 mmHg in the analysis. The repeatability and reliability of the PPG measurements were compared to the LD with Bland Altman plots. Most patients had rest pain (n = 29) or claudication (n = 9). Prior to TP measurement, 24 patients had undergone lower limb revascularization through either a hybrid (n = 3), open (n = 10) or endovascular (n = 11) procedure. The mean absolute difference between PPG and LD measurement values was 15 mmHg (95% confidence interval 12-18 mmHg). 87.5% of lower limbs with significant arterial insufficiency (TP <60 mmHg with LD, n = 49) had a PPG measurement value of <60 mmHg. Conversely, 84.8% of lower limbs that did not exceed the ischemia criterion of TP ≥60 mmHg with LD had a PPG measurement value of ≥60 mmHg. Mean absolute difference of two consecutive PPG measurement values was 4 mmHg (95% CI 3-5 mmHg). The PPG device is a light and affordable option for the assessment of lower limb arterial circulation in primary health care. It is moderately reliable to exclude significant lower limb arterial insufficiency and may reduce unnecessary referrals to the vascular surgery clinic. The repeatability of the PPG device is satisfactory. However, it requires training to use, and the results must always be interpreted with consideration for the patient's clinical status.

Correlation of distance walked in audio signal-modified shuttle walk test with six-minute walk test.

The literature review suggested that the audio signal-modified shuttle walk test (SWTSR) was equally reliable and valid when compared to the conventional shuttle walk test. A comparison of SWTSR with the six-minute walk test (6MWT), which is considered the gold standard in walk tests, allowed us to evaluate the SWTSR and determine its validity and reliability as an alternative or supplement to the 6MWT. The objective of this study was to determine the correlation between the distances walked during a SWTSR and the 6MWT in healthy, normal adults. The study recruited 42 healthy normal adults who underwent 6MWT and SWTSR on the same day. The correlation was assessed by Pearson's correlation coefficient, and agreement between the tests was assessed using a Bland-Altman plot. Additionally, the acceptability of the modified test in comparison to the 6MWT was assessed by the Likert scale. The distances walked (mean ± standard deviation) in the 6MWT and SWTSR were 693.8±58.3 and 951.4±139.7 m, respectively (Pearson's correlation coefficient of 0.918). The distance covered by the study participants in the 6MWT and SWTSR showed a strong correlation with spirometry results. The SWTSR induced a greater physiological response compared to the 6MWT. The acceptability of the SWTSR was comparable to that of the 6MWT. The distance walked in the SWTSR shows a strong positive correlation with the 6MWT and has comparable acceptability with the 6MWT. The SWTSR may provide a better index of the patient's ability for his activities of daily living and may be a better measure for studying exercise tolerance than the 6MWT in certain clinical settings.

Feasibility of position emission tomography derived endocardial wall strain: direct comparison with magnetic resonance using hybrid 13N ammonia PETMR system.

We aimed to evaluate the feasibility of positron emission tomography feature tracking (PETFT) for assessing endocardial wall strain by comparing it with cardiac magnetic resonance (CMR)-derived feature tracking (CMRFT). We enrolled 83 consecutive patients with coronary artery disease who underwent rest-pharmacologic stress 13N-ammonia PETMR (67 males, mean age 66years). PETFT and CMRFT were obtained through simultaneous acquisition with electrocardiography-gated PET and cine-CMR. Global longitudinal and circumferential strain (GLS and GCS) were calculated. Correlations and Bland-Altman plots were employed to evaluate associations, bias, and 95% limit of agreement (LOA) between PETFT and CMRFT. PETFT and CMRFT showed significant correlations (R = 0.57 [95% CI 0.41-0.70], R = 0.71 [95% CI 0.58-0.80], R = 0.59 [95% CI 0.43-0.71], and R = 0.69 [95% CI 0.56-0.79] for rest GLS, rest GCS, stress GLS, and stress GCS, respectively; p < 0.001 for all). Bland-Altman plot showed good agreements, while a systematic error was observed (LOA -10.2-8.8, -8.7-10.7, -10.5-8.5, and -9.4-12.0; bias -0.7, 1.0, -1.0, and 1.3; for rest GLS, rest GCS, stress GLS, and stress GCS; respectively). PETFT has been identified as a feasible technique compared to CMRFT, highlighting its potential as a novel tool for assessing wall strain in routine clinical settings.

Exploring discrepancies in muscle analysis with ImageJ: understanding the impact of tool selection on echo intensity and muscle area measurements.

The aim was to compare the use of different tools within the ImageJ program (polygon vs. segmented line) and their impact on the calculation of muscle area and echo intensity (EI) values in ultrasound imaging of the vastus lateralis muscle. Thirteen volunteers participated in this study. Ultrasound images of the vastus lateralis muscle were acquired using 2D B-mode ultrasonography and analyzed using both the polygon and segmented line tools by the same evaluator. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) assessed the tools' reliability. Bland-Altman plots were employed to verify the agreement between measurements, and linear regression analysis determined proportional bias. A paired t-test was conducted to analyze differences between the tools. The reliability between tools for muscle area calculation was weak (r = 0.000; CV = 138.03 ± 0.34%), while it was excellent for EI (r = 0.871; CV = 15.19 ± 2.96%). The Bland-Altman plots indicated a large bias for muscle area (d = 195.2%) with a proportional bias (p < 0.001). For EI, the bias was (d = 15.2) with proportional bias (p = 0.028). The paired t-test revealed significant differences between the tools for area (p < 0.001) but not for EI (p = 0.060). The study found significant differences in measurements obtained with the polygon and segmented line tools in ImageJ, with the polygon tool showing higher values for muscle area and lower values for EI.

Agreement between lacrimal fluid and serum for detecting urea nitrogen and creatinine in dogs.

To determine whether urea nitrogen and creatinine levels differ in lacrimal fluid (LF) and serum (SER) in nonazotemic (control) and azotemic dogs and whether there is an agreement between LF and SER. A prospective observational study was performed at the Auburn University Small Animal Teaching Hospital between May 2023 and March 2024. Forty control and 38 azotemic dogs were enrolled. Twenty microliters of LF per eye was collected with microcapillary tubes, and 3 mL of blood was drawn. Bland-Altman plot and intraclass correlation coefficient (ICC) were used to evaluate the agreement between LF and SER. There was good agreement between LF and SER levels of urea nitrogen in the control group (Bland-Altman plot mean bias of -0.8108 ± 2.407 mg/dL; ICC of 0.874 [95% CI, 0.773 to 0.934]) and the azotemic group (Bland-Altman plot mean bias of -9.681 ± 23.89 mg/dL; ICC of 0.82 [95% CI, 0.658 to 0.906]). There was poor agreement between LF and SER concentrations for creatinine in the control and azotemic groups, with only 26 dogs with creatinine detectable in LF. Lacrimal fluid and SER concentrations of urea nitrogen showed good agreement in both the control and azotemic groups, whereas poor agreement was found for creatinine in both groups. Measurement of urea nitrogen in LF may provide an alternative to blood for diagnosing uremia. However, additional research is necessary before substituting LF for SER.

Resting energy expenditure in patients with liver cirrhosis: Indirect calorimetry vs. predictive equations.

The objective of our study was to explore the accuracy of previously published prediction equations in predicting resting energy expenditure (REE) in patients with liver cirrhosis (LC). We also aimed to develop a novel equation to estimate REE for Chinese patients with LC. In 90 patients with LC, the agreement between REE measured by Indirect calorimetry (IC) and predictive equations was quantified using paired T-test and visualized using a Bland-Altman Plot. Pearson correlation coefficient (R) was used to measure a linear correlation between REE measured by IC and different predictive equations. Stepwise multiple regression analysis was used to create a new REE equation. The estimated REEs of previous equations were underestimated against REE measured by IC (1610 ± 334 kcal). Lean body mass (LBM) was positively correlated with REE measured by IC (r = 0.723, p < 0.01). The newly derived estimation equation for REE (kcal) was 1274.3 - 209.0 * sex - 5.73 * age + 3.69 * waist circumference + 22.89 * LBM. The newly derived estimation equation was found to have a Pearson-r value of 0.765 compared with REE measured by IC. REE in liver cirrhosis was underestimated by using predictive equations. The new predictive equation developed by using age, sex, waist circumference, and LBM may help estimate REE in Chinese patients with LC accurately and easily.

Secondary fastener (tape) placement on a blood pressure cuff causes interindividual Doppler blood pressure measurement variability in healthy large-breed dogs.

The objective of this study was to compare Doppler blood pressure (DBP) measurements between blood pressure cuffs (BPCs) with and without a secondary fastener (tape) in healthy nonanesthetized large-breed dogs. 28 healthy dogs. Superficial palmar venous arch DBP measurements with and without tape on the BPC were performed in lateral recumbency with Doppler ultrasound. Each method was performed 6 consecutive times, with the final 5 values averaged. Bland-Altman plots were made and limits of agreement calculated. The limits of agreement were -40.8 (95% CI, -55.6 to -26.0) to 45.6 (95% CI, 30.8 to 60.4), indicating that the DBP measured with tape would be expected to be between 40.8 mm Hg below and 45.6 mm Hg above that measured without tape 95% of the time. The mean bias estimate was 2.4 mm Hg (SD, 22.0; 95% CI, -6.1 to 11.0; P = .724), indicating that DBP measurements with tape averaged 2.4 mm Hg higher than without tape. Doppler blood pressure measurements obtained with secondary fasteners on the BPCs differed by > 10 mm Hg compared to the BPCs' standard hook-and-loop fasteners 54% (30 of 56) of the time. Blood pressure cuffs with dysfunctional hook-and-loop fasteners should be replaced due to poor clinical reliability of DBP measurements. However, it is unclear whether Doppler sphygmomanometry is more accurate with the use of traditional Velcro BPC fasteners or with tape BPC fasteners.

Reproducibility of intravoxel incoherent motion quantification in the liver across field strengths and gradient hardware.

To evaluate reproducibility and interlobar agreement of intravoxel incoherent motion (IVIM) quantification in the liver across field strengths and MR scanners with different gradient hardware. Cramer-Rao lower bound optimization was performed to determine optimized monopolar and motion-robust 2D (b-value and first-order motion moment [M1]) IVIM-DWI acquisitions. Eleven healthy volunteers underwent diffusion MRI of the liver, where each optimized acquisition was obtained five times across three MRI scanners. For each data set, IVIM estimates (diffusion coefficient (D), pseudo-diffusion coefficients ( and ), blood velocity SDs (Vb1 and Vb2), and perfusion fractions [f1 and f2]) were obtained in the right and left liver lobes using two signal models (pseudo-diffusion and M1-dependent physical) with and without T2 correction (fc1 and fc2) and three fitting techniques (tri-exponential region of interest-based full and segmented fitting and blood velocity SD distribution fitting). Reproducibility and interlobar agreement were compared across methods using within-subject and pairwise coefficients of variation (CVw and CVp), paired sample t-tests, and Bland-Altman analysis. Using a combination of motion-robust 2D (b-M1) data acquisition, M1-dependent physical signal modeling with T2 correction, and blood velocity SD distribution fitting, multiscanner reproducibility with median CVw = 5.09%, 11.3%, 9.20%, 14.2%, and 12.6% for D, Vb1, Vb2, fc1, and fc2, respectively, and interlobar agreement with CVp = 8.14%, 11.9%, 8.50%, 49.9%, and 42.0%, respectively, was achieved. Recently proposed advanced IVIM acquisition, signal modeling, and fitting techniques may facilitate reproducible IVIM quantification in the liver, as needed for establishment of IVIM-based quantitative biomarkers for detection, staging, and treatment monitoring of diseases.

Ferumoxytol-Enhanced Cardiac Cine MRI Reconstruction Using a Variable-Splitting Spatiotemporal Network.

Balanced steady-state free precession (bSSFP) imaging is commonly used in cardiac cine MRI but prone to image artifacts. Ferumoxytol-enhanced (FE) gradient echo (GRE) has been proposed as an alternative. Utilizing the abundance of bSSFP images to develop a computationally efficient network that is applicable to FE GRE cine would benefit future network development. To develop a variable-splitting spatiotemporal network (VSNet) for image reconstruction, trained on bSSFP cine images and applicable to FE GRE cine images. Retrospective and prospective. 41 patients (26 female, 53 ± 19 y/o) for network training, 31 patients (19 female, 49 ± 17 y/o) and 5 healthy subjects (5 female, 30 ± 7 y/o) for testing. 1.5T and 3T, bSSFP and GRE. VSNet was compared to VSNet with total variation loss, compressed sensing and low rank methods for 14× accelerated data. The GRAPPA×2/×3 images served as the reference. Peak signal-to-noise-ratio (PSNR), structural similarity index (SSIM), left ventricular (LV) and right ventricular (RV) end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were measured. Qualitative image ranking and scoring were independently performed by three readers. Latent scores were calculated based on scores of each method relative to the reference. Linear mixed-effects regression, Tukey method, Fleiss' Kappa, Bland-Altman analysis, and Bayesian categorical cumulative probit model. A P-value <0.05 was considered statistically significant. VSNet achieved significantly higher PSNR (32.7 ± 0.2), SSIM (0.880 ± 0.004), rank (2.14 ± 0.06), and latent scores (-1.72 ± 0.22) compared to other methods (rank >2.90, latent score < -2.63). Fleiss' Kappa was 0.52 for scoring and 0.61 for ranking. VSNet showed no significantly different LV and RV ESV (P = 0.938) and EF (P = 0.143) measurements, but statistically significant different (2.62 mL) EDV measurements compared to the reference. VSNet produced the highest image quality and the most accurate functional measurements for FE GRE cine images among the tested 14× accelerated reconstruction methods. 3 TECHNICAL EFFICACY: Stage 1.

Quantitative neuromuscular monitoring with train-of-four ratio using sonomechanomyography (SMMG): Toward more sensitive evaluation of neuromuscular blockade

In the post-anesthesia care unit, there is a high occurrence of residual neuromuscular blockade, which puts patients at risk of negative consequences such as hypoxia. Assessment based on the train-of-four ratio (TOFR) has been used to avoid residual neuromuscular blockade when the TOFR is greater than 0.9, measured at the adductor pollicis muscle (APM). The most commonly used quantitative neuromuscular monitoring (QNM) modalities include acceleromyography (AMG) and electromyography (EMG). However, the poor user-friendliness of current QNM methods hinders their widespread adoption. To overcome this, we developed a new monitoring method using ultra-fast ultrasound imaging to generate a two-dimensional map of muscle transient motion, i.e., sonomechanomyography (SMMG). SMMG of the APM and AMG of the thumb were used to get the TOFR of 20 normal adults. The results showed no significant difference between the left and right hands for both AMG and SMMG TOFR, with p-values larger than 0.05. In addition, the mean accuracy of SMMG TOFR (0.6% relative error) was higher than AMG (1.4% relative error). Moreover, the Bland–Altman plot showed that all the difference values were within the limits of agreement and the mean bias was 0.02, indicating that the two methods had a very good agreement. In particular, using SMMG did not require additional calibration before testing. Overall, the results demonstrated that the method has the potential as a new QNM approach for further clinical studies to benefit patients in need. To demonstrate its clinical potential, further studies are required to evaluate this method in patients during and post-anesthesia.

Accuracy of Aneroid Versus Digital Sphygmomanometer in Community-Based Screening for Hypertension in Hubballi, Karnataka, India - A Cross-Sectional Study

Background: Hypertension is a significant global health issue, responsible for approximately 7.5 million deaths annually. Even a modest increase of 5 mm Hg in systolic blood pressure (BP) can elevate the risk of fatal stroke and infarction by about 25%. Hence this study aimed to assess the accuracy of aneroid and digital sphygmomanometers relative to the mercury sphygmomanometer. Methodology: This community-based cross-sectional study was conducted in the urban slums of old Hubballi among 270 participants aged 30 years and above. Participants were selected using Probability Proportion to Size from 3 wards. Blood pressures were measured with all three sphygmomanometers and Bland Altman plot analysis was done. Results: The results revealed that the mean difference in systolic blood pressure compared to mercury was -0.57 mmHg for the aneroid and -4.63 mmHg for the digital (p &lt;0.05). For diastolic blood pressure, the mean difference was -0.39 mmHg for the aneroid and -3.43 mmHg for the digital (p &lt;0.05). Bland-Altman analysis showed agreement limits of 66.3% for systolic and 75.2% for diastolic blood pressure with the aneroid sphygmomanometer. Conclusion: The aneroid sphygmomanometer provides more reliable BP readings compared to the digital sphygmomanometer for both systolic and diastolic measurements.

Impact of patient habitus and acquisition protocol on iodine quantification in dual-source photon-counting computed tomography.

Evaluation of iodine quantification accuracy with varying iterative reconstruction level, patient habitus, and acquisition mode on a first-generation dual-source photon-counting computed tomography (PCCT) system. A multi-energy CT phantom with and without its extension ring equipped with various iodine inserts (0.2 to 15.0mg/ml) was scanned over a range of radiation dose levels ( 0.5 to 15.0mGy) using two tube voltages (120, 140kVp) and two different source modes (single-, dual-source). To assess the agreement between nominal and measured iodine concentrations, iodine density maps at different iterative reconstruction levels were utilized to calculate root mean square error (RMSE) and generate Bland-Altman plots by grouping radiation dose levels (ultra-low: ; low: 1.5 to 5; medium: 5 to 15mGy) and iodine concentrations (low: ; high: 5 to 15mg/mL). Overall, quantification of iodine concentrations was accurate and reliable even at ultra-low radiation dose levels. RMSE ranged from 0.25 to 0.37, 0.20 to 0.38, and 0.25 to 0.37mg/ml for ultra-low, low, and medium radiation dose levels, respectively. Similarly, RMSE was stable at 0.31, 0.28, 0.33, and 0.30mg/ml for tube voltage and source mode combinations. Ultimately, the accuracy of iodine quantification was higher for the phantom without an extension ring (RMSE 0.21mg/mL) and did not vary across different levels of iterative reconstruction. The first-generation PCCT allows for accurate iodine quantification over a wide range of iodine concentrations and radiation dose levels. Stable accuracy across iterative reconstruction levels may allow further radiation exposure reductions without affecting quantitative results.

Impact of uncertainty quantification through conformal prediction on volume assessment from deep learning-based MRI prostate segmentation

ObjectivesTo estimate the uncertainty of a deep learning (DL)-based prostate segmentation algorithm through conformal prediction (CP) and to assess its effect on the calculation of the prostate volume (PV) in patients at risk of prostate cancer (PC).MethodsThree-hundred seventy-seven multi-center 3-Tesla axial T2-weighted exams from biopsied males (66.64 ±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm$$\\end{document} 7.47 years) at risk of PC were retrospectively included in the study. Assessment of PV based on PI-RADS 2.1 ellipsoid formula (PVref\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{ref}}$$\\end{document}) was available for included patients. Prostate segmentations were obtained from a DL model and used to calculate the PV (PVDL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{DL}}$$\\end{document}). CP was applied at a confidence level of 85% to flag unreliable pixel segmentations of the DL model. Subsequently, the PV (PVCP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{CP}}$$\\end{document}) was calculated when disregarding uncertain pixel segmentations. Agreement between PVDL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{DL}}$$\\end{document} and PVCP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{CP}}$$\\end{document} was evaluated against the reference standard PVref\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{ref}}$$\\end{document}. Intraclass correlation coefficient (ICC) and Bland–Altman plots were used to assess the agreement. The relative volume difference (RVD) was used to evaluate the PV calculation accuracy, and the Wilcoxon Signed-Rank Test was used to assess statistical differences. A p-value < 0.05 was considered statistically significant.ResultsConformal prediction significantly reduced RVD when compared to the DL algorithm (RVD = − 2.81 ±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm$$\\end{document} 8.85 and RVD = −8.01 ±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm$$\\end{document} 11.50). PVCP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{CP}}$$\\end{document} showed a significantly larger agreement than PVDL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{DL}}$$\\end{document} when using the reference standard PVref\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{ref}}$$\\end{document} (mean difference (95% limits of agreement) PVCP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{CP}}$$\\end{document}: 1.27 mL (− 13.64; 16.17 mL) PVDL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{DL}}$$\\end{document}: 6.07 mL (− 14.29; 26.42 mL)), with an excellent ICC (PVCP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{{\\rm{PV}}}}_{{CP}}$$\\end{document}: 0.97 (95% CI: 0.97 to 0.98)).ConclusionUncertainty quantification through CP increases the accuracy and reliability of DL-based PV assessment in patients at risk of PC.Critical relevance statementConformal prediction can flag uncertain pixel predictions of DL-based prostate MRI segmentation at a desired confidence level, increasing the reliability and safety of prostate volume assessment in patients at risk of prostate cancer.Key PointsConformal prediction can flag uncertain pixel predictions of prostate segmentations at a user-defined confidence level.Deep learning with conformal prediction shows high accuracy in prostate volumetric assessment.Agreement between automatic and ellipsoid-derived volume was significantly larger with conformal prediction.Graphical

Screening for obstructive sleep apnea in the memory clinic: A comparison of questionnaires, pulse oximetry, and polysomnography.

Obstructive sleep apnea (OSA) is highly prevalent among older adults and has been associated with cognitive decline and dementia risk. The suitability of screening tools for detecting OSA in memory clinic settings is unclear. To evaluate the utility and validity of the STOP-Bang questionnaire (SBQ) and pulse oximeter as a screening tool, compared to gold-standard polysomnography (PSG) in older adults attending a memory clinic. Participants aged over 50 with new onset cognitive/mood concerns attended a memory clinic, then completed the SBQ, oximetry, and PSG. The SBQ and oximetry's accuracy in detecting moderate-severe and severe OSA was evaluated using receiver operating curves. Intraclass correlation and Bland-Altman plots compared the oximeter's adjusted oxygen desaturation index (ODI-Ox) and PSG's apnea-hypopnea index (AHI-PSG). Of 194 participants (mean age = 65.6, 64 males) who completed PSG, 184 completed the SBQ, and 138 completed oximetry. SBQ demonstrated limited performance for moderate-severe OSA (sensitivity = 52%, specificity = 62%, AUC = 0.600) and severe OSA (sensitivity = 18%, specificity = 87%, AUC = 0.577). Oximetry was satisfactory for moderate-severe OSA (sensitivity = 67%, specificity = 73%, AUC = 0.769) and severe OSA (sensitivity = 50%, specificity = 88%, AUC = 0.730). The diagnostic performance was improved with new cut-offs at ODI-Ox ≥ 11 for AHI-PSG ≥ 15 and ODI-Ox ≥ 20 for AHI-PSG ≥ 30. Bland-Altman plots and intraclass correlation indicated acceptable agreement for oximetry. The findings suggest that while the SBQ may be unsuitable to detect moderate or severe OSA for older adults with cognitive impairment, oximetry may be a viable screening tool. Given OSA treatment can optimize sleep and may slow cognitive decline, routine screening for OSA should be part of memory clinic assessments.

Accelerated Phase Contrast MRI with Use of Resolution Enhancement Generative Adversarial Neural Network

BackgroundCardiovascular magnetic resonance (CMR) phase-contrast is used to quantify blood flow. We sought to develop a complex-difference reconstruction for inline super-resolution of phase-contrast (CRISPFlow) to accelerate phase-contrast imaging. MethodsCRISPFlow was built on the super-resolution generative adversarial network. The model was trained and tested (4:1 ratio) using retrospectively identified phase-contrast images from 2020 patients (56 ± 16 years; 56% men) referred for clinical 3T CMR at a single center from 2018 to 2023. For testing, ascending aortic flow images collected with 2.5 × 1.9 mm2 resolution using generalized autocalibrating partially parallel acquisitions (GRAPPA) were used to synthesize images with 7.5 × 1.9 mm2 resolution. CRISPFlow subsequently restored spatial resolution. In a prospective validation study of 38 participants (57 ± 15 years; 14 men) and 16 healthy individuals (42 ± 16 years; 6 men), CRISPFlow was applied to phase-contrast images collected with 7.5 × 1.9 mm2 resolution with use of GRAPPA and was compared to GRAPPA-accelerated images collected with 2.3 × 1.9 mm2 resolution. A blur metric was used to quantify sharpness. Aortic flow measurements were obtained semi-automatically. Statistical evaluation included analysis of variance, Bland-Altman analysis, Pearson correlation coefficient (r). ResultsCRISPFlow reconstruction was successful in all cases. CRISPFlow reduced blurring in retrospective (0.35 vs. 0.47, P < 0.001) and prospective (0.34 vs. 0.48, P < 0.001) images with 7.5 × 1.9 mm2 resolution. Blurring in CRISPFlow images was similar to blurring in images with 2.5 × 1.9 mm2 (0.35 vs. 0.35, P = 0.4082) and 2.3 × 1.9 mm2 (0.34 vs. 0.32, P < 0.001) resolution. Bland-Altman differences in forward volume (-2 ml [-8 to 3ml]), regurgitant volume (0ml [-3 to 2ml]), and a fraction (0% [-5 to 4%]) showed good agreement between the two techniques in a retrospective cohort. Differences in forward volume (1ml [-11 to 14ml]) also showed good agreement in the prospective cohort. There was a strong correlation (all r > 0.90) between GRAPPA and CRISPFlow measurements of flow in both studies. ConclusionWe demonstrated the potential of complex-difference reconstruction for inline super-resolution of phase-contrast flow (CRISPFlow) to accelerate phase contrast.

Reproducibility of three six-minute walk tests in patients with COPD referred for pulmonary rehabilitation

Introduction and ObjectivesThe six-minute walk test (6MWT) is used to assess functional capacity in patients with COPD. A significant number of studies have shown that most patients walk further in a second 6MWT. Research on a further increase in the six-minute walk distance (6MWD) during a 3rd test performed in accordance with current guidelines has not been done. Therefore, this study aimed to investigate 1) the reproducibility of three 6MWTs in patients with COPD referred for pulmonary rehabilitation (PR) and 2) predictors of improvement on a third 6MWT. Materials and MethodsBefore the start of PR, 1167 COPD patients (50% male, age: 62±9 years; FEV1: 42±18%pred) performed three 6MWTs (6MWT1, 6MWT2, and 6MWT3). A predetermined threshold of ≥42m improvement in 6MWD in consecutive 6MWT’s was used to identify improvers. Reproducibility between tests was assessed using a Bland-Altman plot and logistic regression analyses were performed to assess effects of sex, age, body mass index, GOLD-stage, 6MWD, use of supplemental oxygen and use of walking aids. ResultsGenerally, the 6MWD improved (6MWT1: 343±115m; 6MWT2: 367±115m; 6MWT3: 381±116m). 210 patients (18%) improved ≥42m from 6MWT2 to 6MWT3. The Bland-Altman plot showed that the 95% limits of agreement of 6MWT3 vs 6MWT2 exceeded 42m, indicating that 6MWT2 is not reproducible. Predictors of improvement in 6MWT3 were GOLD stage I/II and a low 6MWD (<350m) in the previous two 6MWTs. ConclusionsThese results indicate that three 6MWTs may be required to obtain the largest pre-PR functional capacity in COPD patients. Patients with a 6MWD <350m and GOLD-stage I/II are more likely to improve ≥42m in a third 6MWT.

Reliability of MScanFit Motor Unit Number Estimation in the Trapezius Muscle.

MScanFit motor unit number estimation (MUNE) is the most recent MUNE method which has shown promising results in extremity muscles, but it has not been applied to bulbar muscles. Bulbar muscles are particularly important in the diagnosis of amyotrophic lateral sclerosis (ALS). This study aimed to investigate the feasibility and reliability of MScanFit MUNE in the accessory nerve and trapezius muscles. A total of twenty healthy participants were examined twice within 1-2 weeks. We extracted the MScanFit MUNE and size parameter, and compound muscle action potential (CMAP) amplitude values. The reliability of these parameters was assessed using the intra-rater coefficient of variation (CoV), intraclass correlation coefficient (ICC), and Bland-Altman plots. We also correlated MUNE values with CMAP amplitudes using correlation coefficients. Mean MUNE values (Day 1 = 132.1 and Day 2 = 137.4), CMAP amplitudes (Day 1 = 9.71 mV and Day 2 = 10.10 mV) and size parameters did not differ between the two sessions (p > 0.05). CoV showed excellent reliability for MUNE values, size parameters, and CMAP amplitudes (CoV < 7%) whereas ICCs showed moderate reliability for MUNE values (ICC = 0.619), poor to moderate reliability for size parameters (between 0.393 and 0.689), and good reliability for CMAP amplitude (ICC = 0.864) There was no correlation between MUNE values and CMAP amplitudes. MScanFit MUNE is applicable and mostly reliable in the trapezius muscle. Further studies in patients are needed to investigate the sensitivity of MScanFit in this muscle in detecting motor unit loss, particularly in ALS.

Preoperative Evaluation of Lingual Cortical Plate Thickness and the Anatomical Relationship of the Lingual Nerve to the Lingual Cortical Plate via 3T MRI Nerve-Bone fusion.

To evaluate the reliability of 3 T MRI nerve-bone fusion in assessing the lingual nerve (LN) and its anatomical relationship to the lingual cortical plate prior to the impacted mandibular third molar (IMTM) extraction. The MRI nerve and bone sequences used in this study were 3D-T2-weighted fast field echo (3D-T2-FFE) and fast field echo resembling a CT using restricted echo-spacing (FRACTURE), respectively. Both sequences were performed in 25 subjects, and the resulting 3D-T2-FFE/FRACTURE fusion images were assessed by two independent observers. Semi-quantitative analyses included assessments of overall image quality, image artifacts, nerve continuity, and the detectability of five intermediate points (IPs). Quantitative analyses included measurements of the lingual cortical plate thickness (LCPT), vertical distance (V1* and V2*) and the closest horizontal distance (CHD) between the LN and the lingual cortical plate. Reliability was evaluated using weighted Cohen's kappa coefficient (κ), intraclass correlation coefficient (ICC) and Bland-Altman plots. Differences in LCPT between 3D-T2-FFE/FRACTURE fusion images and one-beam computed tomography (CBCT) were compared using independent samples T-tests or Mann-Whitney U tests. The fusion images demonstrated that the LN continuity score was 3.00 (1.00) (good), with 88% (44/50) of LNs displayed continuously to the IMTM level. Intra-reader agreement for nerve continuity was moderate (κ = 0.527), as was inter-reader agreement (κ = 0.428). The intra-reader and inter-reader agreement for LCPT measurements at the neck, mid-root and apex of the IMTM were all moderate (ICC > 0.60). Intra-reader agreements for V1*, V2* and CHD were moderate to excellent (ICC = 0.904, 0.967 and 0.723, respectively), and inter-reader agreements for V1*, V2* and CHD were also moderate to excellent (ICC = 0.948, 0.941 and 0.623, respectively). The reliability of LCPT measurements between 3D-T2-FFE/FRACTURE fusion and CBCT was moderate (ICC = 0.609-0.796). The 3D-T2-FFE/FRACTURE fusion technique demonstrated potential feasibility for the identification of the LN and its relationship to the lingual cortical plate, as well as for the measurement of LCPT. This study has generated a dataset that is capable of simultaneously defining the LN and LCPT.

Comparing three-dimensional zero echo time (3D-ZTE) lung MRI and chest CT in the evaluation of systemic sclerosis-related interstitial lung disease.

Systemic sclerosis (SSc) is a chronic disease that can cause interstitial lung disease (ILD), a poor prognostic factor in SSc patients. Given the concerns over radiation exposure from repeated CT scans, there is a growing interest in exploring radiation-free imaging alternatives like MRI for ILD evaluation. The aim of this study is to assess the efficacy of three-dimensional zero echo time (3D-ZTE) MRI in assessing SSc-related ILD compared to the thin-slice chest CT. This prospective single-center study investigated 65 SSc patients. SSc patients underwent CT, 3D-ZTE lung MRI, and pulmonary function tests (PFTs) within a week. Three independent reviews visually quantified ILD extent on ZTE and CT imaging and the correlation of ILD extent with PFTs was analyzed. Statistical analyses were performed, including the intraclass correlation coefficient (ICC), Kruskal-Wallis tests, Bland-Altmann analysis, and correlation analyses between imaging results and PFTs. ILD was detected in 45 patients via CT. 3D-ZTE MRI identified ILD in 41 (91.1%) of these cases, demonstrating a strong correlation with CT in assessing ILD severity (r = 0.986, p < 0.001). The median ILD extent scores were 5% for CT and 6% for 3D-ZTE MRI. Interobserver reliability for 3D-ZTE MRI was excellent, with ICC values ranging from 0.853 to 0.969. The analysis also revealed significant negative correlations between ILD extent on ZTE MRI and lung function, particularly FVC. 3D-ZTE lung MRI is a reliable and radiation-free alternative to chest CT for evaluating SSc-related ILD, with a strong correlation in assessing total fibrosis and ground-glass opacities, though limitations remain in detecting fine reticulations and coarseness. Question Can 3D-ZTE MRI replace thin-slice chest CT as a radiation-free method for assessing SSc-related ILD? Findings 3D-ZTE lung MRI showed an excellent agreement with thin-slice CT in evaluating ILD extent in SSc patients (r = 0.986, p < 0.001). Clinical relevance 3D-ZTE lung MRI provides a reliable, radiation-free alternative to CT for assessing ILD extent in SSc patients, ensuring safer longitudinal monitoring and management.